Memory
, ❏ Pps = participants
❏ Acoustically similar = sound
Coding, capacity and duration of memory the same
❏ Semantically similar = means
Research on coding the same
❏ “The format which information is stored in various memory
stores” Evaluation
❏ Researcher = Baddeley
P Identifies a clear difference between 2 memory stores
Procedure
E Idea that STM uses acoustic coding and LTM uses
semantic coding most of the time has stood a lot of the time
❏ Gave different lists of words to 4 groups of Pps to remember
❏ Group 1 = acoustically similar words C Important in understanding the memory system and
❏ Group 2 = acoustically dissimilar words has contributed to the Multi store model of memory
❏ Group 3 = semantically similar words
❏ Group 4 = semantically dissimilar words P Baddeley’s study used quite artificial stimuli rather than
❏ Pps were shown the original words and were asked to recall meaningful material
them in the correct order
E Word lists had no personal meaning to Pps
Findings
Baddeley’s findings may not tell us much about coding in
❏ When this task was done immediately (testing STM), Pps
different kinds of memory tasks, especially in everyday life
tended to do worse with acoustically similar words
When processing meaningful information people may use
❏ When recalled after a 20 min interval (LTM) PPs did worse in semantic coding more even in STM
the semantically similar words
❏ Findings suggest that info is coded acoustically in STM and C Suggests that findings have limited application
LTM is coded semantically
, ❏ Chunking = grouping
sets of of digits or
Coding, capacity and duration of memory letters into units or
chunks
Research on capacity
❏ “The amount of information that can be stored in memory” Evaluation
Digit span P Jacob’s study has been replicated
❏ Researcher = Jacobs E Jacob’s study = old, lacked adequate controls
❏ Measured digit span (Pps may have been distracted)
❏ Pps were asked to recall a set of digits/ letters
immediately after they were shown and would only move
Findings have been confirmed by other better
on if they recalled in the correct order e.g recall 4 digits
and only moving onto 5 digits if recalled correctly controlled studies
❏ Mean span for digits = 9.3 and mean span for letters =
7.3 C Jacob’s study is a valid test for digit span in STM
Span of memory and chunking P Millers study may have overestimated the
capacity for STM
❏ Researcher = Miller
❏ Noted that things come in 7s e.g 7 days a week, 7 E Cowan reviewed other research and concluded
deadly sins that capacity for STM is only about 4 ± 1 chunks
❏ Believed the capacity for STM = 7 ± 2
❏ Noted that people can recall 5 words as easily as
C Suggests the lower end of Millers estimate (5
recalling 5 letters by a chunking
items) is more appropriate than 7 items
, Coding, capacity and duration of memory
Research on duration Evaluation
❏ “The length of time information can be held in memory”
P Stimulus was artificial in Peterson and
Short term memory (STM) Peterson’s study
❏ Researcher = Peterson and Peterson
YCG
E Recalling consonant syllables does not reflect
❏ Tested 24 students in 8 different trials each
❏ Each trial = student was given a trigram (3 consonant syllable) to remember e.g everyday memory activities = meaningless
YCG stimuli
❏ The student was also given a 3 digit number to count backwards from outloud
to prevent mental rehearsal of the trigram
❏ Each trial the Pps were told to stop after different period of time -> 3,6,9,12,15 or
C Study lacked external validity
18 secs
❏ After 3 secs recall = 80 % avg, after 18 secs = 3% avg P Bahrick’s study had high external validity
❏ Suggest that duration of STM is around 18 seconds and there is rehearsal
E Researchers investigated meaningful
Long term memory (LTM)
memories
❏ Researchers = Bahrick
❏ Studied 392 American Pps aged 17-74 yrs old When studies on LTM were conducted with
❏ High school yearbooks were obtained and recall was tested in various ways: meaningless photos to be remembered, recall
❏ Photo recognition test with 50 photos
❏ Free recall rates= lower
❏ Pps tested within 15 yrs of graduation = 90% accurate in photo recognition;
after 48 years = declined to 70% C Suggests that Bahrick’s findings reflect a
❏ Free recall was less accurate than photo recognition = 60% vs 30 %
respectively
more real estimate of the duration of LTM
❏ LTM may last a lifetime with some material